The invention relates to rotary internal combustion engines of the type disclosed in U.S. Pat. No. 2,988,065 and particularly to such an engine designed for operation as a stratified charge engine. Prior stratified charge rotary combustion engines are disclosed in U.S. Pat. Nos. 3,246,636, 3,387,595, 3,344,778, 3,508,530 and 3,805,747.
The problem of pollution resulting from exhaust emission discharge by internal combustion engines is one of the major problems facing modern society. One of the proposed approaches for minimizing this problem is to design the engine for operation with a stratified charge. By stratified charge operation it is meant engine operation with the fuel-air mixture or charge being non-uniformly distributed in each working chamber so that the chamber has at least one region in which the fuel-air mixture is relatively rich at the time combustion is initiated in the chamber. Various types of stratified charge engine configurations have been proposed in the past. To be successful, the stratified charge engine configuration must be able to significantly reduce all three of the major harmful constituents in the engine exhaust; namely, the carbon monoxides, the hydrocarbons and the nitrogen oxide compounds. In addition, the exhaust emission reduction must be achieved without any serious adverse effects on engine performance or engine fuel consumption.
Aforementioned stratified charge U.S. Pat. Nos. 3,387,595, 3,508,530 and 3,805,747 all disclose stratified charge rotary combustion engines in which the engine is provided with an auxiliary chamber in the engine housing and in which combustion is initiated. In such stratified charge rotary combustion engines the burning combustion gases are transferred from the auxiliary combustion chamber through a relatively small discharge passage into the main combustion chamber. The losses associated with this transfer of the burning combustion gases necessarily results in a reduction in engine performance and fuel consumption.
U.S. Pat. No. 3,246,636 discloses a stratified charge rotary combustion engine in which fuel is discharged directly into the engine working chambers at a point adjacent a spark plug for immediate ignition of the fuel by the plug. Although this stratified charge engine configuration shows considerable promise, difficulty has been experienced in providing satisfactory operation over the entire range of engine output and speed.
U.S. Pat. No. 3,344,778 shows a stratified charge rotary engine configuration in which an auxiliary combustion chamber in effect is formed in each working face of the rotor and into which fuel is discharged directly from the engine housing. With this latter configuration, all the engine fuel is supplied to each of the auxiliary chambers in the rotor faces and, therefore, it is difficult to achieve adequate mixture of air with this fuel in order to achieve complete combustion.